How Long Can Betta Fish Go Without Food (Before getting ill)

How Long Can Betta Fish Go Without Food

Betta fish (Betta splendens), also known as Siamese Fighting Fish, are great pets to have. They are beautiful fish to look at, intelligent, and generally quite hardy fish. They can go for weeks without food, but how long can a betta fish go without food before getting ill?

In a healthy tank, betta fish can go for 12 to 14 days without food before becoming lethargic or ill. Betta fish will hunt out leftover food from the bottom of the tank to keep them going. So before you take your vacation, overfeed them a little, and they’ll be fine.

With that being said, there are several factors to consider before leaving your betta fish unattended and without fish food for any length of time, and this blog post will look at those factors and provide tips on how to feed your betta while you are away!

Make sure to check out our Betta Fish Care Guide And Species Overview.

How Long Can Betta Fish Go Without Food (5 Factors To Think About)

If you are considering leaving your betta for a period of time, they should be fine without food for up to 14 days, but there are some important things to think about, other than just feeding them no matter how many days.

Below are 5 of the main factors to consider:

  1. Tank Size

Betta fish can grow up to around 12cm, and they require a tank size of at least 40 liters – however, the bigger your betta’s tank is, the better. If you’re going away for a week or two, then make sure that the tank is not too cramped an environment, especially with other inhabitants.

Your betta fish can survive in the right environment by tapping on fat reserves when it needs to, but stress levels need to be kept to a minimum for the body to function at its best. If you are going to leave them for extended periods and regularly, it may be best to invest in a bigger tank.

  1. Temperature Of The Water

If the water temperature is too high or low, then your betta may not be able to live without food for that length of time.

If you’re going away on your summer vacation, it’s best to keep the tank somewhere cool and if you’re going away during winter, make sure the tank is kept warm (at around 78-82°F/26-28°C).

Betta’s are tropical fish and prefer warmer water, but they can become stressed if the water becomes too warm, which is never good for a betta fish.

Keeping a cooler tank will offer some benefits, especially if you are going for more than a week, as it will slow down your betta’s metabolism and burn food calories at a slower rate so that they will survive longer without food.

  1. Tank Environment

To keep your betta happy and healthy, it’s best to have a few hiding places for them in their tank. This means having some plants or artificial decorations in there as well.

If you don’t want live plants, then silk ones will also work fine, but live plants are also a small part of a bettas diet in the wild and will provide them with some extra calories.

I’ve already mentioned that a larger tank would benefit your betta, and if you want to help betta survive while you are on vacation, water pollution needs to be kept to a minimum. Your betta tank needs to be at its optimum with the tank water checked thoroughly before you go.

  1. Age Of Your Betta Fish

Bettas that are younger will need to eat more often than older bettas. If you have a young betta, it’s best to ask how long they have been in their current environment before deciding how long they can go without food.

The other aspect of age is how long they’ve been with you. If it’s only a few weeks, then your betta fish would only go without food for a much shorter length of time than if your betta has had you as their owner for several months and knows the routine of feeding time.

Picture Of A Betta Fish
A Betta Fish
  1. Your Betta Fish’s Health Condition

If any illness or disease is present, how long betta fish can go without food will be shorter.

They won’t have the energy to look for any leftover scraps at the bottom of their tank, and if your betta has been ill in the past, it’s best to err on the side of caution when you are planning how long your betta can survive without food while away from home.

How Many Days Can Betta Fish Go Without Food Comfortably

Although I have told you that betta fish can go without food for up to 14 days, this is not ideal, and the potential for harm is there. A person can live without food for several weeks, but you wouldn’t want to do it as the potential for internal damage or organ failure is very real.

Betta fish can go for many days without food quite comfortably and taking small vacations of 3-5 days should be a walk in the park for them.

How Often Do You Feed A Betta Fish

As this is a post on betta eating habits, we may briefly cover how often to feed a betta and what betta fish eat.

A healthy betta fish will cope much better when left for an extended period without food, and if you are planning to leave them, it is important to understand what a good diet consists of to keep your betta fish healthy.

Many betta owners actually overfeed their fish and end up with lots of waste build up in the tank, so how often do you feed a betta fish, and how much should you feed them?

A betta fish’s stomach is tiny, in fact, it is about the size of their eye, so they will not need large amounts of food to become full and content. When feeding your betta, the amount of food depends mostly on their size.

Small Betta fish require around one pinch of food (or two if it’s Betta food) once a day. Betta fish are carnivores, and although they can eat some vegetables, this should be the exception, not the rule.

Betta Fish are usually picky eaters and will only pick at their food when it’s first put into the tank, so if you feed your betta in the morning, don’t worry if there is still betta food left in the bowl at night.

As Betta Fish’s grow larger, they will obviously need more food per day, and if you want to increase your betta’s growth rate, this is one option that can help you do that.

How much food they eat per feed can remain the same, but you can increase the feeds to twice a day as they grow bigger. Keeping an eye on ammonia levels in your betta tank will help you gauge if you are overfeeding or not, as you will often get spikes in the levels when the water pollution increases.

A betta that has been fed healthily will cope much better when they are left without food for extended periods.

What Do Betta Fish Eat

Betta fish are carnivorous fish, and they will eat most meaty foods. Betta fish can be fed on commercial betta food, frozen bloodworms, brine shrimp, and live plants (although only rarely).

As carnivores, a bettas diet should contain mostly protein-rich items such as worms or insects. If you want to feed your betta some vegetables, this is fine once in a while, but it should not be the norm.

Freeze Dried Bloodworms For Betta Fish
Freeze Dried Bloodworms For Betta Fish

Although betta will eat plants if you have them in your tank, they will usually nibble at the edges and not be overly interested in them.

Fasting Your Betta Fish

Regular feeding is fine, although, with almost all fish, I find it is best to fast them for a couple of days in the week, and I do this every week. I find it helps avoid ammonia spikes from the rotting food, and fish will always find scraps lying around the tank when hungry.

Fasting will naturally keep waste levels down as fish will poop less, and they will eat the excess food particles usually left to rot.

Not feeding your betta for a day or two is actually much healthier than overfeeding. It’s true, and I would recommend that you do some further research as it will certainly contribute to keeping your bettas healthy and may combat weight gain. Bettas will not be fed regularly when in the wild, and they will usually live longer than they do in captivity.

How To Feed Betta Fish While On Vacation

Even though your betta can survive without food for up to 14 days, there are other ways to feed your betta fish while on vacation.

Automatic Feeders For Betta Fish

If you prefer not to leave your betta fish without food for 12-14 days, then one option is to use an automatic fish feeder. There are several options to choose from, such as pyramid blocks (or feeder blocks) or battery-operated feeders.

Many automatic feeders work on a timer and will clamp on the top of the tank, releasing food at the correctly programmed intervals. Automatic fish feeders may not be the best option for a betta fish tank because they require a lidless tank, and bettas are known to jump from their tanks.

automatic fish feeder for aquariums
Automatic fish feeder for aquariums.

Slow Release Food Blocks

Betta Food Blocks or pyramid blocks operate as a slow-release form of feeding. These blocks are placed at the bottom of the tank and will slowly dissolve, releasing natural ingredients which are healthy for most fish species.

If you choose to use food blocks, make sure they are suitable for your betta, and get some good quality ones that will dissolve at a consistent rate, so your betta is not overfed while you are away.

Food blocks should not be used as a regular feeding method but will work perfectly for those occasions when you are away.

You will usually find feeder blocks or an automatic fish feeder at your local fish store, pet stores, or online.

Ask A Friend Or Neighbor To Feed Your Betta

If you have a good friend or neighbor that you can trust as a pet sitter, you could leave your Betta in their care while on vacation.

They will need to be given instructions on when and how much to feed your Betta fish and will be able to keep an eye on them without having any other responsibility.

If they are not comfortable feeding your betta, it’s worth considering the automatic feeder or food block.

Preparing Your Betta Tank For Before Your Vacation

Your vacation is just around the corner, and there are a few things that you need to do with your betta tank before you go to avoid any health problems when you return.

Below is a quick checklist to help you to get organized:

Make sure your Betta is eating well and is in good health

If your betta fish is in good health, it will minimize the risk of illness striking while you are away. Stress will also impact your betta’s health, so the chances of illness striking will be reduced by keeping stress levels down.

Tank Conditions should be at their optimum level

A major factor that can lead to stress or illness is poor water quality. It would be recommended to carry out a full water change the week before you go away, or at least a 30-50 percent change a day or two before you go. Make sure to add a water conditioner if you perform a large water change.

Make sure to vacuum the gravel or substrate thoroughly, removing food and poop waste that may decompose and cause a damaging ammonia spike while you are away.

Check the water parameters thoroughly with a test kit, and don’t overfeed your betta before you go.

Smaller tanks will need the most care as water conditions change more rapidly in such a small body of water.

If you have live plants in your tank, they will help with the biological lifecycle, helping to oxygenate the water and assisting the development of good bacteria. Having good bacteria in your tank will help with the nitrogen lifecycle keeping ammonia, nitrate, and nitrite levels down and the water quality at its best.

Raised ammonia levels can starve the water of oxygen and cause unwanted stress to your fish.

Check Your Aquarium Equipment Is In Good Working Order

Check all equipment, including filters, pumps, lights (ensure that they are working correctly). The most important piece of equipment will be the heater as betta fish need a consistent temperature to maintain good health.

Betta keepers should have a heater that can maintain a stable temperature between 78-82°F/26-28°C.

It’s important to ensure the temperature is just right and cannot drop too low or fluctuate in any way during your time away. Make sure you move the betta tank somewhere safe, away from direct sunlight that may heat the aquarium water beyond a comfortable temperature during the day.

On the flip side, make sure your tank is not close to any draughts and make sure that your room temperature is comfortable.

I have mentioned previously that it can be beneficial to drop the temperature of your tank to slow the metabolism of your betta fish. You can do this if you will be away for more than just a few days, as bettas will be happy, providing the temperature remains consistent.

You can drop the temperature to between 72-76°F/22-24.5°C, but make sure to return it to normal as soon as you return.

check your aquarium temperature
Check your aquarium heater temperature.

Your betta may appear a little more sluggish, but it won’t eat so much and will not need to burn any fat reserves that it has.

An air pump is not necessary as betta fish can get the oxygen they need from the water’s surface if necessary.

If you are using a filter, make sure it is well maintained and running properly before going away. Bacterial filters need cleaning once every two weeks or so, while mechanical and chemical filters should not require maintenance at all during your time away from home.

Check The Water Level

Be careful not to overfill your tank as betta fish can jump, and this can be a problem if you are leaving the tank for any length of time. Betta fish have been known to jump out and swim down into pipes, so it’s important that your betta is always secure in their aquarium.

Betta fish are used to living in shallow water as they live in rice patties, so they will survive with the water level being slightly lower than normal.

Consider Adding Aquarium Salt

It is not necessary, but some Betta owners add aquarium salt. It helps protect against parasites and also helps Betta fish heal from illness.

The recommended dosage is one tablespoon per gallon of water or half that for smaller doses of salt. Make sure you don’t add too much as this can harm your Betta’s health and cause stress to the point where they cannot cope with being in their tank.


Although betta fish can survive for up to 14 days without food, I would never recommend that you do it; however, it is useful to know, and if you have no other option, follow the steps above.

When you return home, all being well, your Betta should be healthy and happy, waiting for you!

Jon O'Connell

I have kept both marine and freshwater fish and set up almost 100 aquariums. Happy to share my knowledge and experience to help others enjoy keeping healthy and happy fish.

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